23 ≤ C(52,12,2) ≤ 24

Created by: LJCR

Method of Construction: Multiple of (26,6,2) covering

Lower Bound: Horsley, Theorem 11, r=5, d=4

  1  2  3  6 15 16 27 28 29 32 41 42
  1  4 12 16 17 20 27 30 38 42 43 46
  1  5  9 11 14 26 27 31 35 37 40 52
  1  7  9 13 19 26 27 33 35 39 45 52
  1  8 16 18 21 24 27 34 42 44 47 50
  1 10 16 22 23 25 27 36 42 48 49 51
  2  4  9 18 23 26 28 30 35 44 49 52
  2  5  7 12 24 25 28 31 33 38 50 51
  2  8 13 14 20 22 28 34 39 40 46 48
  2 10 11 17 19 21 28 36 37 43 45 47
  3  4 10 13 14 24 29 30 36 39 40 50
  3  5  7  8 17 23 29 31 33 34 43 49
  3  9 20 21 25 26 29 35 46 47 51 52
  3 11 12 18 19 22 29 37 38 44 45 48
  4  5  7 15 21 22 30 31 33 41 47 48
  4  6  8 11 19 25 30 32 34 37 45 51
  5  6  7 10 18 20 31 32 33 36 44 46
  5  9 13 14 16 19 31 35 39 40 42 45
  6  9 17 22 24 26 32 35 43 48 50 52
  6 12 13 14 21 23 32 38 39 40 47 49
  7 11 13 14 16 26 33 37 39 40 42 52
  8  9 10 12 15 26 34 35 36 38 41 52
 11 15 19 20 23 24 37 41 45 46 49 50
 13 14 15 17 18 25 39 40 41 43 44 51